Skip to main content

Could A Blood Test Replace Lumbar Punctures In Alzheimer’s Diagnosis - Gyrus Group

 

A New Alzheimer’s Blood Test: A Diagnostic Breakthrough

For decades, the path to a definitive Alzheimer’s disease (AD) diagnosis has been challenging, relying on a combination of cognitive testing, expensive PET scans, or invasive lumbar punctures. A reliable and accessible blood test has long been a primary goal for the field, promising to significantly improve the diagnostic process for both patients and clinicians.

A landmark new study from researchers at the Mayo Clinic, published in Alzheimer’s & Dementia, shows that this goal is moving firmly into clinical reality. Their work validates a powerful new blood test using plasma-based biomarkers — marking a significant step forward for both clinical and legal communities.

The Breakthrough: A Blood Test with Near-CSF Accuracy

Critically, the study evaluated the performance of plasma biomarkers in a real-world setting — a cohort of over 500 patients from an outpatient memory clinic. This population reflects the true complexity of cognitive assessment: multiple health issues, variable presentations, and diagnostic uncertainty.

The biomarker at the centre of the study is phosphorylated tau 217 (p-tau217), a protein closely associated with Alzheimer’s pathology.

Key findings include:

  • High Sensitivity (95%): Accurately identified patients with Alzheimer’s.
  • High Specificity (82%): Effectively ruled out those without the disease.
  • Strong Overall Accuracy (AUC 0.91): Comparable to cerebrospinal fluid (CSF) tests, long considered the gold standard.

Notably, the researchers demonstrated that a “two-cutpoint” model allowed 86% of patients to receive a definitive positive or negative result based on a single blood test — substantially streamlining the diagnostic process.

Important Consideration: The Role of Kidney Function

The study also noted that p-tau217 levels in plasma can be influenced by renal function. Specifically, patients with reduced kidney function (as measured by eGFR) exhibited higher levels of p-tau217, independent of Alzheimer’s diagnosis. This is due to the kidneys’ role in protein clearance — reduced renal filtration can lead to protein accumulation in the bloodstream.

While this does not negate the utility of the biomarker, it underscores the importance of interpreting results alongside renal function data to maintain diagnostic accuracy.

Medico-Legal Relevance

As blood-based biomarkers like p-tau217 enter clinical use, they will inevitably influence medico-legal assessments. Whether in claims concerning cognitive impairment, testamentary capacity, or questions of delayed diagnosis, this tool will become increasingly relevant.

For experts and solicitors alike, an awareness of both the strengths and caveats of these tools will be essential as standards of care evolve.

0121 485 6000

contact@gyrusgroup.com

 

Labels:

Comments

Post a Comment

Popular posts from this blog

What Is Post-Traumatic Amnesia Following A Traumatic Brain Injury - Gyrus Group

  Post-traumatic amnesia is a transient state following a traumatic brain injury, where brain function is temporarily altered, disrupting cognitive and behavioural functioning (Parker et al., 2022). The accurate diagnosis of post-traumatic amnesia is critical for understanding the appropriate clinical management and prognosis of the patient following a traumatic brain injury. However, in many cases these impairments are not accurately diagnosed, negatively impacting clinical care as well as medicolegal claims. Post-traumatic amnesia was first described in 1930s by British neurologists Ritchie Russell and Charles Symonds (Russel, 1932; Symonds, 1937). Post-traumatic amnesia refers to the time between the onset of a traumatic brain injury and the time that patients can encode and retrieve new memories. It was noted that patients typically exhibit a range of cognitive, behavioural and perceptual deficits, as well as considerable variation in their clinical presentations. Russell ...
Post a Comment
Read more

The Importance Of 3T MR Imaging - Gyrus Group

Jenny is a 25-year-old architect, who was hit by a car while cycling training for a triathlon. She was wearing a helmet. She had sustained significant orthopaedic injuries, and at the scene was noted by the paramedics to be repetitive and agitated. By the time she had arrived at hospital she had had Morphine, but was considered alert and orientated, she had visible signs of a head injury. Her day of injury CT head scan showed bruising outside the skull, but no skull fracture or bleeding in or around the brain. Jenny had undergone significant physical rehabilitation, and as she returned to work, she had ongoing problems with headaches and fatigue. She noted that she was making errors in the workplace and felt that her thought processes were now slower than they used to be. She felt not as sharp at her job and had a negative performance review for the first time. Some 18 months after the injury, her solicitor instructed a neurologist as part of the Gyrus Group team. They noted the a...
Post a Comment
Read more

Understanding The Consequence Of Multiple Concussions. Animal Model Of Concussion Mimics Clinical Symptoms Seen In Humans - Gyrus Group

  Following damage to the central nervous system (CNS), immune cells in the brain, known as microglia, are activated. Microglia are critical for protecting neural function and they have an important role in clearing debris and modulating the inflammatory response. However, following CNS injury , microglia can become dysregulated and play a key role in neurodegeneration. Chahin et al., (2025) recently published in Communications Biology, present an animal model of single and repetitive concussions, which was able to reliably induce cognitive and learning impairments in the absence of deficits in motor function, a key confound in the assessment of cognition. The model did not induce macroscopic brain injury and did not induce hemorrhage, edema, contusion, bruising, skull fracture or cell death. As a result, the model was able to mimic human concussions, where cognitive impairments are typically seen in the absence of abnormalities on neuroimaging scans. Following repetitive con...
Post a Comment
Read more